How pedestrian-connected cities may actually be smarter cities

New insights into neuroscience offer some intriguing parallels to urban dynamics – suggesting an “urban connectome” may be the key to city vitality.

Portland, Oregon in 1905, looking north along 5th Avenue at Yamhill Street.

A few years ago, the book Emergence by Stephen Johnson included a fascinating discussion of the relationship between cities and other natural structures, including ant colonies and software systems. One of the most fascinating comparisons was to the structure of the human brain. The lesson was that we can learn a lot from such comparisons.

Now, once again, a new finding in brain science might just have a lot to offer to our understanding of cities.

We all know that there has been great advancement in understanding the human genome in recent years. We’re learning fascinating lessons about the highly patterned structure of our genes – and about how the genome uses those connected patterns to do more with much less. (Though vast, the genome is remarkably smaller and more elegant than we once thought.)

There’s a corollary in brain science too, in the way the neurons work together. As with genes, it now seems less important whether certain elements are in certain places, and more important how the structure forms inter-connected patterns – again, managing to do more with less.

Following the naming precedent in genetics, this structure is now being called the neural “connectome” (because it’s a structure that’s similar to “genome”) and the race is on to map this structure and its most important features. (Much of this work is being advanced by theNIH’s Human Connectome Project)

What do these insights have to do with cities? As Stephen Johnson noted, there is more in common between the two structures than might appear. There is good reason to think that, as with brains, a lot of what happens in cities has more to do with the overall pattern of connections, and less to do with particular elements.

As Jane Jacobs pointed out over half a century ago – also described by Johnson – the city is a kind of “intricate ballet” of people interacting, going about their plans, and shaping the life of the city, from the smallest scales to the largest. This intricate pattern is complex, but it’s far from random. As Jacobs argued, it exhibits a high degree of order — what she called “organized complexity.”

And it’s physical, starting at the scale of the sidewalk, and encompassing all the other movements and connections of urban activity. “Sidewalk contacts are the small change from which a city’s wealth of public life may grow,” she wrote. We may also be plugged in electronically by telephone and now Internet, but (as research by Robert Putnam and others is showing) the root of the system is the physical proximity with the people we know and work with.

More than that, this pattern of connections generates remarkable efficiencies, forming a kind of “urban metabolism.” Jacobs has since become famous for observing highly local “knowledge spillovers,” casual transfers of knowledge about a job or a new tool, that help to grow new enterprises and new economic activities. Her insight, now called a “Jacobs Externality” by economists in her honor, helps to explain how a city generates wealth. As we have written before, this phenomenon might well help to explain why cities are so efficient with resources per person, relative to other places.

In the same vein, the brain scientists offer some other important insights. For one thing, it is not just that density per se is important (of neurons, or of people) but that the patterns of connections are important. So we have to be able to ensure that the “neural pathways” can form – in the case of a person’s brain, that the person is healthy and well-nourished enough to remember, and learn. In the case of cities, we have to ensure that we have well-connected, walkable cities, facilitating a lot of cross-connection.

The brain scientists even believe now that this pattern of neural cross-connection is key to the formation of consciousness. In effect, the different parts of the brain are joined up into a larger system, and the result is that the system self-organizes into a state that is smarter and more aware.

Something similar might be going on with well-connected cities: they can self-organize to become “smarter” in their ability to generate great urban vitality with fewer resources. But this is true only if their “neurons” (the people) are able to be connected, especially physically connected, in this way.

That lesson of self-organization carries an important implication for planners and urban designers. It suggests we need to focus less on the specific elements in relation to one another – and how we might imagine they are best placed – and focus more on how we can help them to self-organize into more complex (and more efficient) patterns.

On the other hand, human brains do not start from scratch as we once thought, nor do societies – we all have patterns that we learn and apply to new situations. So too, cities have patterns that facilitate this network structure. Like a good memory, the best walkable cities of history offer us many good reusable patterns to create vibrant, walkable, resource-efficient cities.

A corollary is that in our automobile-connected suburbs, it seems we have been replicating this pattern of connections – but only with heavy and unsustainable inputs of resources. If we want more resource-efficient cities – and more resilient economies – then it seems we will have to look much harder at this dynamic, and ways to exploit it to our advantage.

How can we do this, concretely? The brain scientists are working hard to map the connective patterns of particular brains, to get some idea of how the patterns tend to form characteristically within the “human connectome.” For cities, it seems we might do something equally useful: map the characteristic urban patterns that have proven most conducive to this connected vitality, and that also do not interfere with – or better yet promote – the capacity for urban self-organization.

In a sense we already do this when we speak of design types, or planning models. But this work is usually very constrained by parochial debates within the architecture and urban design disciplines over “progressivism” versus “historicism.” The result is that there has been a stagnation of real progress in this area. At worst, we have slipped into what Jacobs called a “neurosis” of “imitating empiric failure, and ignoring empiric success.”

By contrast, the brain scientists point to another, less ideologically constrained path. It seems we might have much to learn from a more open, aggressive mapping of the genetic patterns of such an “urban connectome,” looking at a range of cities around the world – and over centuries of evolution.